Benzoic acid

Benzoic acid - yog qhov nyuaj tus neeg sawv cev ntawm cov chav kawm ntawv ntawm carboxylic los yog organic acid nrog cov tshuaj mis C6H5COOH. Qhov no tshuaj compound yuav tau hais tias nws twb tsim los ntawm hloov ib hydrogen atom uas txuas mus rau ib tug carbon atom ntawm lub benzene nplhaib rau ib tug carboxy pab pawg neeg.

Benzoic acid nyob rau hauv zoo li yog ib tug tsis muaj kob crystalline khoom nrog ib tug ntom ntawm 1.27 g / cm³ thiab ib tug molecular ceeb thawj los ntawm 122,1 g / tus nas. Melting point C6H5COOH sib npaug zos rau 122,41 ° C thiab cov kub - 249,2 ° C. Nyob rau hauv 1 liter ntawm dej yog tau yaj 2.9 g C6H5COOH substance. Acidity yog 4,202, lub refractive index yog 1,5397.

Lub npe yog muab tau los ntawm benzoin, los ntawm uas nyob rau hauv lub xyoo pua 16th (uas yog thawj piav los ntawm Nostradamus nyob rau hauv 1556, thiab ces Blaise de Vigenère nyob rau hauv 1596), ib yam khoom uas thawj cais los ntawm sublimation. Rau ib ntev lub sij hawm, qhov no tej yam ntuj tso compound tseem nyob xwb qhov ntawm acid.

Nyob rau hauv 1832 los ntawm ib tug chemist J. Liebig twb xub piav txog tus qauv ntawm benzoic acid, thiab nyob rau hauv 1875 ib tug German physiologist Ernst Leopold Salkowski soj ntsuam nws noj thiab antiseptic thaj. Cov ntsev yog siv raws li ib tug preservative nyob rau hauv khoom noj khoom haus cov khoom, thiab benzoic acid nws tus kheej yog ib qho tseem ceeb raw khoom rau lub synthesis ntawm ntau lwm yam organic tebchaw. Muaj ntau housewives thiab niaj hnub no siv no cov cim muaj peev xwm ntawm cov carboxylic acid rau sij hawm ntev cia lingonberry berries tsis muaj ntxiv preservatives (txawm tsis muaj ntxiv qab zib) los yog tshwj xeeb ua kev.

Esters ntawm benzoic acid thiab ntsev ntawd yog hu ua benzoates. Zoo cov yam ntxwv ntawm muaj ntxhiab tebchaw thiab carboxylic acids combines benzoic acid. Nws tshuaj zog yog txiav txim los ntawm lub xub ntiag ntawm lub uas muaj ntxhiab nplhaib thiab ib tug carboxyl pab pawg neeg.

Rau cov uas muaj ntxhiab nplhaib yam ntxwv electrophilic hloov cov tshuaj tiv thaiv mas rau peb carbon atom, uas qhov chaw txiav txim txheeb ze mus rau lub carboxyl pab pawg neeg.

Qhov thib ob tswvyim yog ib tug hloov cov tshuaj tiv thaiv mus rau nyob rau hauv qhov chaw ntawm lub hydrogen ntawm lub carboxyl pab pawg neeg thiab qeeb qeeb.

Tag nrho cov tshuaj hais rau carboxylic acids, yog tseem ntxwv rau C6H5COOH.

Vim lub cim antiseptic thiab noj zog, benzoic acid yog siv nyob rau hauv Canning. Nws yog siv raws li ib tug xov tooj ntawm cov khoom noj additives E210-E213. Benzoic acid blocks lub enzymes thiab cov metabolism hauv teeb meem unicellular kab mob. Tsaug rau qhov kev txiav txim inhibited qhov kev loj hlob ntawm yeasts, pwm thiab ntau tus kab mob-ua kab mob. Siv benzoic acid los yog nws cov sodium, potassium los yog poov hlau ntsev.

Cov tshuaj yeeb dej caw uas muaj peev xwm ntawm seeb antimicrobial kev ua si xwb nyob rau hauv acidic cov khoom noj. Yog hais tias intracellular pH tsawg tshaj los yog sib npaug zos rau 5, tus co fermentation ntawm zib yog txo los ntawm 95%. Miv nyuas siv zug acid thiab benzoates nyob rau hauv lub pH ntawm cov khoom noj. Txiv hmab txiv ntoo kua txiv (uas muaj citric acid), sparkling dej haus (muaj CO2), uas tsis yog-dej cawv (muaj phosphoric acid), pickles (acetic acid) los yog lwm yam fwm cov zaub mov acidification acid thiab nws ntsev. Pom ntau nyob rau hauv lub preservation ntawm khoom noj khoom haus yog nyob rau hauv lub chav 0.05-0.1%.

Raws li toluene feem ntau tsim benzoic acid. Kev npaj nws ntws los ntawm cov tshuaj tiv thaiv tswvyim methylbenzene oxidation nrog poov tshuaj permanganate. Nyob rau ib tug coj mus muag hauv paus yog ib tug tshwj xeeb organic compound ua los ntawm ib nrab oxidation ntawm toluene nrog oxygen. Cov txheej txheem yuav siv sij hawm qhov chaw nyob rau ib tug tshwj xeeb catalyst. Rau lub chaw soj nstuam benzoic acid yog pheej yig thiab muaj reagent. Rau tag nrho syntheses, nws yuav muaj kev dawb huv los ntawm recrystallization los ntawm aqueous tov. Nyob rau hauv cov ntaub ntawv no, cov cuab yeej ntawm siab solubility nyob rau hauv dej kub thiab txom nyem solubility nyob rau hauv dej txias.

Benzoic acid pom dav siv raws li ib tug preservative ntawm khoom noj khoom haus, cov tshuaj thiab organic synthesis raws li nws yog tau ntau yam organic tshuaj, xws li dyes. Tsis tas li ntawd, nws yog siv nyob rau hauv lub tshuaj kev lag luam los yog nyob rau hauv txoj kev xyaum ntawm analytical laboratories.